App Magic: On-Site at Open Mobile Summit

SAN FRANCISCO — The panel was stuffed with mobile app heavy hitters including a former Google vice president and the architect of Trulia’s popular mobile app.

Their mission was simple: Explain to the assembled audience Wednesday at the Open Mobile Summit the how-to of building a captivating app that keeps users coming back.

And keep in mind a couple points. With smaller devices – smartphones and smaller – users most certainly want to minimize their own data input. Also, the smaller the device, the fewer push notifications and similar, welcome news to the typical user.

That is: what’s acceptable on a 10-inch tablet might be wildly wrong on a connected wristwatch and, for the mobile app developer, these are facts that have to be digested.

Another factor: ever more traffic is stampeding into mobile. At Trulia, for instance, Steven Yarger said that the company’s mobile traffic three years ago was maybe five percent of total traffic. “Today it is nearing 50%.”

That’s the norm. Mobile is emerging as the dominant platform, mainly because it is consumed on devices that we have with us wherever we go,

Mobile also is unique, said Vishal Sharma, the former Google vice president who headed the Google Now initiative. “Location for sure is crucial with mobile. The device is with you at all times. What are you hoping to accomplish? Inferring intent becomes critical for the app developer, it’s the most important thing.”

That is, what does this user appear to want to get out of this contact? Guess wrong and it may alienate the user. Keep guessing right and, probably, the user will keep coming back, suggested the panelists.

Knowing what to base guesses on is becoming key. Raj Singh, CEO of Tempo Ali, an augmented calendar app, noted: “We used to believe more data is better. Not anymore. We have realized that there is an 80/20 rule. Two or three data sources get us 95% of what we want. The next dozen don’t move the needle.”

That means apps developers have to learn what matters and what needs to be ignored about this user, now.

“It’s very complicated,” said Sharma. “If it appears to be simple you don’t know to consume the data.” He added, “It will keep getting more complicated.”

Last thought came from the panel’s moderator, Ravi Mhatre, a partner at investment firm Lightspeed Ventures. Said Mhatre as the panel neared its end, “I am hearing, to a person on the panel, that the bar has been raised. The right things have to show up in limited real estate. There is great opportunity in mobile. But if you want people to use your app, the standards are quite high.”